Known image forming apparatus include a process cartridge including a photosensitive body cartridge and a developing cartridge. In some image forming apparatus, the photosensitive body cartridge is configured to be attachable to and detachable from a main body of the image forming apparatus, and the developing cartridge is configured to be attachable to and detachable from the photosensitive body cartridge.
The photosensitive body cartridge includes a photosensitive drum to which a developing agent is supplied. The photosensitive drum is an example of a photosensitive body. The developing cartridge includes a developing roller for supplying a developing agent to a surface of the photosensitive drum. The main body of the image forming apparatus has an opening that is configured to open upward and enables the process cartridge, in which the developing cartridge is joined to the photosensitive body cartridge, to be attached to and detached from the main body.